There is a need for a device capable of rotating an image by or within a device. Examples of situations where such a device could be used include the treatment, diagnosis, or measurement and characterization of cyclotropia (a type of strabismus in which one or both eyes are rotated from their normal orientations); devices intended to demonstrate or simulate cyclotropia to patients, patients' families, health care practitioners and students, or the general public; novelty devices which as part of their effect or as their intended purpose rotate an image which is being viewed; or any simple or complex optical device which as part of its function involves rotation of an image in or by said device.